Pulse width modulated solenoid

ABSTRACT

A pulse width modulated solenoid control valve is described, wherein the valve includes a polymer fluid control body. The body includes a segmented fluid flow path for providing strength to the fluid control body assembly. Stand off ribs are provided to improve assembly into a control manifold. A casing forms an integral flux tube. A tapered push rod is used to reduce flux shorting.

CROSS-REFERENCE TO RELATED APPLICATION

The instant application claims priority to U.S. Provisional PatentApplication Ser. No. 60/474,774, filed May 30, 2003, the entirespecification of which is expressly incorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to solenoid control valves, andmore particularly to a pulse width modulated solenoid control valve forcontrolling hydraulic functions of a transmission for a vehicle.

BACKGROUND OF THE INVENTION

Various solenoid designs have been used in the automotive industry,including those for use in conjunction with automatic transmissionsystems. For example, automatic transmission control systems generallyemploy solenoids in order to control the pressure and flow of thetransmission fluid. In this manner, the control of transmission fluidpressure can be used to engage and disengage a transmission clutch inresponse to an electrical input signal supplied to the solenoid, or thecontrol of transmission fluid pressure can be used to maintaintransmission line pressure.

Generally, solenoids employ a solenoid control valve to aid in theregulation of the fluid flow by the solenoid. An example of a solenoidcontrol valve can be found in U.S. Pat. No. 4,998,559 to McAuliffe etal., the entire specification of which is incorporated herein byreference. Recently, the use of pulse width modulated solenoids hasbecome more prevalent in certain automotive applications.

Although pulse width modulated conventional solenoid control valves havebeen somewhat successful in meeting the demands of the automotiveindustry, these pulse width modulated solenoid control valves can befurther improved upon, e.g., in the areas of cost, quality, performance,and the like.

Accordingly, there exists a need for new and improved pulse widthmodulated solenoid control valves.

SUMMARY OF THE INVENTION

A new and improved solenoid control valve is provided, in accordancewith the general teachings of the present invention. More specifically,a new and improved pulse width modulated solenoid control valve isprovided, in accordance with one embodiment of the present invention

The solenoid control valve preferably employs a plastic control valvebody that preferably includes a segmented flow path that adds strengthto the supply tube portion. In accordance with a preferred embodiment ofthe present invention, a stepped coil portion is preferably provided. Inaccordance with another preferred embodiment of the present invention,an actuation rod is preferably provided that is tapered adjacent to andcontacting the armature so as to reduce flux shorting and improveoperating characteristics. Accordingly, the solenoid control valve ofthe present invention preferably provides a characteristic performancecurve.

In accordance with a first embodiment of the present invention, asolenoid fluid control valve is provided, comprising: (1) a fluidcontrol body adapted for being received in a fluid housing, said fluidcontrol body including a central cavity, and having a pressure supplypassage at a first end and a radially extending pressure controlpassage; (2) a feed supply tube positioned in said central cavity, saidfeed supply tube including an outer diameter in communication with thepressure control passage, and including an inner bore operably connectedto said pressure supply passage, said feed supply tube being supportedin said central cavity of said fluid control body by way of a radiallyand axially extending wall, said wall being segmented into a pluralityof longitudinally extending flow chambers, said feed supply tubeincluding a valve receiving chamber area; (3) a valve seat portion beingmade of a metallic material and press fit into said fluid control body,said valve seat portion including a valve seat and a passage incommunication between said valve seat and said pressure control passage;(4) a valve contained in said valve receiving chamber operable toselectively close off communication between said pressure supply passageand said pressure control passage; and (5) a solenoid for opening saidvalve in response to a signal.

In accordance with a second embodiment of the present invention, asolenoid fluid control valve is provided, comprising: (1) a fluidcontrol body adapted for being received in a fluid housing, said fluidcontrol body including a central cavity, and having a pressure supplypassage at a first end and a radially extending pressure controlpassage; (2) a feed supply tube positioned in said central cavity, saidfeed supply tube including an outer diameter in communication with thepressure control passage, and including an inner bore operably connectedto said pressure supply passage, said feed supply tube being supportedin said central cavity of said fluid control body by way of a radiallyand axially extending wall, said wall being segmented into a pluralityof longitudinally extending flow chambers, said feed supply tubeincluding a valve receiving chamber area; (3) a valve seat portion beingmade of a metallic material and press fit into said fluid control body,said valve seat portion including a valve seat and a passage incommunication between said valve seat and said pressure control passage;(4) a valve contained in said valve receiving chamber operable toselectively close off communication between said pressure supply passageand said pressure control passage; (5) a solenoid for opening said valvein response to a signal, wherein said solenoid includes a central axisand has a coil wound around a bobbin, spaced from and positioned aroundsaid central axis, said coil having radially stepped radial innerdiameters; (6) a casing member for attaching said solenoid to said fluidcontrol body; a portion of said casing member extending into the steppedportion of said coil for forming a flux tube therein; and (7) anarmature axially movable within said bobbin.

In accordance with a third embodiment of the present invention, asolenoid fluid control valve is provided, comprising: (1) a fluidcontrol body adapted for being received in a fluid housing, said fluidcontrol body including a central cavity, and having a pressure supplypassage at a first end and a radially extending pressure controlpassage; (2) a feed supply tube positioned in said central cavity, saidfeed supply tube including an outer diameter in communication with thepressure control passage, and including an inner bore operably connectedto said pressure supply passage, said feed supply tube being supportedin said central cavity of said fluid control body by way of a radiallyand axially extending wall, said wall being segmented into a pluralityof longitudinally extending flow chambers, said feed supply tubeincluding a valve receiving chamber area; (3) a valve seat portion beingmade of a metallic material and press fit into said fluid control body,said valve seat portion including a valve seat and a passage incommunication between said valve seat and said pressure control passage;(4) a valve contained in said valve receiving chamber operable toselectively close off communication between said pressure supply passageand said pressure control passage; (5) a solenoid for opening said valvein response to a signal, wherein said solenoid includes a central axisand has a coil wound around a bobbin, spaced from and positioned aroundsaid central axis, said coil having radially stepped radial innerdiameters; (6) a casing member for attaching said solenoid to said fluidcontrol body; a portion of said casing member extending into the steppedportion of said coil for forming a flux tube therein; (7) an armatureaxially movable within said bobbin; (8) a pole piece assembly adjacentsaid armature and interposed between said bobbin and said fluid controlbody; and (9) a control rod extending along said central axis andthrough said pole piece assembly for opening of said valve, said controlrod including a tapered end.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of the solenoid control valve of thepresent invention;

FIG. 2 is a side view of the control valve body of the presentinvention;

FIG. 3 is a top view of the control valve body of the present invention;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 2;

FIG. 6 is a sectional view taken along line 6-6 of FIG. 2;

FIG. 7 is a sectional view taken along line 7-7 of FIG. 2;

FIG. 8 is a second partially broken away sectional view of the valvebody of the present invention;

FIG. 9 is a performance curve of the operational characteristics of thepresent invention when operating at 40 psi;

FIG. 10 is a performance curve of the operational characteristics of thepresent invention when operating at 120 psi; and

FIG. 11 is a performance curve of the operational characteristics of thepresent invention when operating at 215 psi.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

Referring to the Figures generally, and FIGS. 1-8 specifically, there isprovided a solenoid control valve generally shown at 10, in accordancewith the general teachings of the present invention. The solenoidcontrol valve includes a fluid control body generally indicated at 12,and a solenoid portion generally indicated at 14. By way of anon-limiting example, the fluid control body 12 is preferably adaptedfor being received in a fluid manifold housing in a valve body of atransmission.

The fluid control body 12 preferably includes a central cavity 16,wherein the central cavity 16 preferably includes a fluid supply passage18 and a fluid control passage 20. These passages preferably communicatewith either a supply line in the manifold or a control line, as isreadily known in the art. A feed supply tube 22 is preferably integrallymolded with the fluid control body 12. Feed supply tube 22 preferablyincludes an outer diameter 24, which is in communication with thecontrol passage 20, and preferably includes an inner bore 26 incommunication with the supply passage 18 through laterally extendingport 28. The feed supply tube 22 is preferably supported in the cavity16 by at least one or more segmented areas 30, best shown in FIG. 6.Preferably, there are three segmented flow passages on each side of thefeed supply tube 22, as shown in FIG. 6. The feed supply tube 22preferably includes a valve receiving area 32.

A valve seat-forming portion 34 is preferably made out of a metalmaterial and is press fit into the feed supply tube 22. The outerdiameter of the valve seat-forming portion 34 is preferably press fitinto the valve receiving area 32. By this arrangement, fluid passage isallowed to flow axially through the segmented area 30, while the websforming the segmented area absorb press loads on the valve seat member34. An alignment shelf 36 is preferably provided on the control body forproviding proper depth of alignment of the valve seat member 34. A ballvalve 38 is preferably held between the valve seat 40 and the valveretainer portion 32. A return spring 35 preferably biases the ball valve38 toward valve seat 40. The valve seat member 34 preferably provides apassageway 42 to the control passage 20. The valve 40 is preferablyoperable to selectively cut off supply of flow from the supply channel18 to the control passage 20.

The valve seat member 34 is preferably press fit into the flux washer 62forming a pole piece assembly 64. In a preferred embodiment, the fluxwasher 62 is preferably a stamped member and the valve seat member 34 ispreferably a screw turned member. Assembly of these pieces togetherreduces the cost of the assembly.

Solenoid portion 14 is preferably secured to the fluid control body 12.An O-ring 44 is preferably disposed between the fluid control body 12and the pole piece assembly 64. The solenoid 14 preferably includes acentral axis A-A and has a coil 46 wound around a nonmagnetic bobbinmember 48. The bobbin member 48 is preferably stepped radially, andincludes a radially outward wall 52 and a radially inward wall 54. Aone-piece casing member 50 preferably includes a radially extending fluxtube forming annular portion 56. The casing 50 also preferablycrimpingly attaches the solenoid 14 to the body 12 by way of the crimpedportion 58. An armature 60 is preferably provided, which fits within thewall 54 and is axially movable in response to a current in the coil. Thepole piece assembly 64 is preferably secured between the lower portionof the bobbin 48 and the control body 12. The pole piece assembly 64preferably includes a center orifice 64, which allows the valve seatmember 34 to be press fit therein.

The control rod 66 preferably has a tapered upper end 67 and is movablewithin the member 34. The armature 60 preferably moves the control rod66. The tapered pin preferably reduces magnetic flux shorting, therebyimproving performance without sacrificing strength.

Assembly standoffs 69 are preferably provided. These standoffs arepreferably axially radially extending rib members. These rib members actto preferably provide precise positioning of the casing 50 in the finalsolenoid control valve of the present invention. Specifically, aretention groove 76 is preferably provided that is engaged by a clipmember (not shown) when securing the control valve 10 in a fluidmanifold housing in a valve body of a transmission, for example. In thepast, getting the fluid control body 12 axially positioned properly inthe manifold housing for alignment of the clip with slot 76 has beenproblematic. These ribs ensure precise alignment during assembly for theclip to engage slot 76. A preferred embodiment has two ribs 76 spaced180° apart and a wider rib 76 a positioned 90° between these ribs 76.

The coil 46, bobbin 48 and coil contacts 70 are preferably overmolded toform connector 72. This forms a one-piece assembly that also preferablyincludes an armature cage assembly 72A portion that preferably holdsarmature 60 and its biasing spring 74 in place upon securement of thecasing 50 to the fluid control body 12.

Set forth in FIGS. 9 through 11 are transfer function progressionsshowing the duty cycle performance of the pulse width modulation of thesolenoid of the present invention when operating with 40, 120 and 215pounds per square inch of fluid pressure applied at the supply passage.As shown therein, the performance characteristics are optimized in thedesign of the present invention.

The description of the invention is merely exemplary in nature and,thus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A solenoid fluid control valve, comprising: a fluid control bodyadapted for being received in a fluid housing, said fluid control bodyincluding a central cavity, and having a pressure supply passage at afirst end and a radially extending pressure control passage; a feedsupply tube positioned in said central cavity, said feed supply tubeincluding an outer diameter in communication with the pressure controlpassage, and including an inner bore operably connected to said pressuresupply passage, said feed supply tube being supported in said centralcavity of said fluid control body by way of a radially and axiallyextending wall, said wall being segmented into a plurality oflongitudinally extending flow chambers, said feed supply tube includinga valve receiving chamber area; a valve seat portion being made of ametallic material and press fit into said fluid control body, said valveseat portion including a valve seat and a passage in communicationbetween said valve seat and said pressure control passage; a valvecontained in said valve receiving chamber operable to selectively closeoff communication between said pressure supply passage and said pressurecontrol passage; and a solenoid for opening said valve in response to asignal.
 2. The invention according to claim 1, wherein said solenoidincludes a central axis and has a coil wound around a bobbin, spacedfrom and positioned around said central axis, said coil having radiallystepped radial inner diameters.
 3. The invention according to claim 2,further comprising a casing member for attaching said solenoid to saidfluid control body; a portion of said casing member extending into thestepped portion of said coil for forming a flux tube therein.
 4. Theinvention according to claim 3, further comprising an armature axiallymovable within said bobbin.
 5. The invention according to claim 4,further comprising a pole piece assembly adjacent said armature andinterposed between said bobbin and said fluid control body.
 6. Theinvention according to claim 5, further comprising a control rodextending along said central axis and through said pole piece assemblyfor opening of said valve, said control rod including a tapered end. 7.The invention according to claim 1, wherein the fluid supply passage isa radially extending passage and said fluid control passage is axiallyextending.
 8. The invention according to claim 1, wherein said valve isa ball valve.
 9. The invention according to claim 5, wherein said polepiece assembly includes a stamped flux washer member and a press-fitvalve seat member.
 10. The invention according to claim 2, wherein saidbobbin and said coil member are over molded in an integral unit with aconnector member.
 11. The invention according to claim 4, wherein a cageis formed for retaining the armature therein.
 12. The inventionaccording to claim 1, wherein said fluid control body is made of apolymer material.
 13. The invention according to claim 1, wherein saidfluid control body has an upper radially extending lip member and atleast one axially protruding positioning rib extending therefrom. 14.The invention according to claim 1, wherein said fluid control body hasa performance curve progression of any of those depicted in any of FIGS.9-11.
 15. A solenoid fluid control valve, comprising: a fluid controlbody adapted for being received in a fluid housing, said fluid controlbody including a central cavity, and having a pressure supply passage ata first end and a radially extending pressure control passage; a feedsupply tube positioned in said central cavity, said feed supply tubeincluding an outer diameter in communication with the pressure controlpassage, and including an inner bore operably connected to said pressuresupply passage, said feed supply tube being supported in said centralcavity of said fluid control body by way of a radially and axiallyextending wall, said wall being segmented into a plurality oflongitudinally extending flow chambers, said feed supply tube includinga valve receiving chamber area; a valve seat portion being made of ametallic material and press fit into said fluid control body, said valveseat portion including a valve seat and a passage in communicationbetween said valve seat and said pressure control passage; a valvecontained in said valve receiving chamber operable to selectively closeoff communication between said pressure supply passage and said pressurecontrol passage; a solenoid for opening said valve in response to asignal, wherein said solenoid includes a central axis and has a coilwound around a bobbin, spaced from and positioned around said centralaxis, said coil having radially stepped radial inner diameters; a casingmember for attaching said solenoid to said fluid control body; a portionof said casing member extending into the stepped portion of said coilfor forming a flux tube therein; and an armature axially movable withinsaid bobbin.
 16. The invention according to claim 15, further comprisinga pole piece assembly adjacent said armature and interposed between saidbobbin and said fluid control body.
 17. The invention according to claim16, further comprising a control rod extending along said central axisand through said pole piece assembly for opening of said valve, saidcontrol rod including a tapered end.
 18. The invention according toclaim 15, wherein the fluid supply passage is a radially extendingpassage and said fluid control passage is axially extending.
 19. Theinvention according to claim 15, wherein said valve is a ball valve. 20.The invention according to claim 16, wherein said pole piece assemblyincludes a stamped flux washer member and a press-fit valve seat member.21. The invention according to claim 15, wherein said bobbin and saidcoil member are over molded in an integral unit with a connector member.22. The invention according to claim 15, wherein a cage is formed forretaining the armature therein.
 23. The invention according to claim 15,wherein said fluid control body is made of a polymer material.
 24. Theinvention according to claim 15, wherein said fluid control body has anupper radially extending lip member and at least one axially protrudingpositioning rib extending therefrom.
 25. The invention according toclaim 15, wherein said fluid control body has a performance curveprogression of any of those depicted in any of FIGS. 9-11.
 26. Asolenoid fluid control valve, comprising: a fluid control body adaptedfor being received in a fluid housing, said fluid control body includinga central cavity, and having a pressure supply passage at a first endand a radially extending pressure control passage; a feed supply tubepositioned in said central cavity, said feed supply tube including anouter diameter in communication with the pressure control passage, andincluding an inner bore operably connected to said pressure supplypassage, said feed supply tube being supported in said central cavity ofsaid fluid control body by way of a radially and axially extending wall,said wall being segmented into a plurality of longitudinally extendingflow chambers, said feed supply tube including a valve receiving chamberarea; a valve seat portion being made of a metallic material and pressfit into said fluid control body, said valve seat portion including avalve seat and a passage in communication between said valve seat andsaid pressure control passage; a valve contained in said valve receivingchamber operable to selectively close off communication between saidpressure supply passage and said pressure control passage; a solenoidfor opening said valve in response to a signal, wherein said solenoidincludes a central axis and has a coil wound around a bobbin, spacedfrom and positioned around said central axis, said coil having radiallystepped radial inner diameters; a casing member for attaching saidsolenoid to said fluid control body; a portion of said casing memberextending into the stepped portion of said coil for forming a flux tubetherein; an armature axially movable within said bobbin; a pole pieceassembly adjacent said armature and interposed between said bobbin andsaid fluid control body; and a control rod extending along said centralaxis and through said pole piece assembly for opening of said valve,said control rod including a tapered end.
 27. The invention according toclaim 26, wherein the fluid supply passage is a radially extendingpassage and said fluid control passage is axially extending.
 28. Theinvention according to claim 26, wherein said valve is a ball valve. 29.The invention according to claim 26, wherein said pole piece assemblyincludes a stamped flux washer member and a press-fit valve seat member.30. The invention according to claim 26, wherein said bobbin and saidcoil member are over molded in an integral unit with a connector member.31. The invention according to claim 26, wherein a cage is formed forretaining the armature therein.
 32. The invention according to claim 26,wherein said fluid control body is made of a polymer material.
 33. Theinvention according to claim 26, wherein said fluid control body has anupper radially extending lip member and at least one axially protrudingpositioning rib extending therefrom.
 34. The invention according toclaim 26, wherein said fluid control body has a performance curveprogression of any of those depicted in any of FIGS. 9-11.